Multiple Diamond Earths Could Exist in Milky Way

According to new research out of Ohio State University, several giant planets made up of more than 50 percent diamond, called “carbon super-Earths,” could exist in the Milky Way Galaxy. Researchers at the school recreated the temperatures and pressures of Earth’s lower mantle to study how diamonds form there.

“The surfaces of these planets are likely to be very unappealing places,” says Wendy Panero, associate professor in the School of Earth Sciences at Ohio State. “It’s still fun to think about planets that might have huge diamonds throughout: centimeter or bigger diamonds just below the surface.”

The study found that it’s possible the planets could be as big as 15 times the mass of Earth. Also, according to Panero, there is so much diamond in the interior that the planet wouldn’t function like Earth. “On Earth, we have plate tectonics because the interior has solid rock slowly in motion to let the interior heat escape,” she says. “This then leads to volcanoes, with which come the gasses that make atmospheres. On these diamond planets, because of the hard diamond, there is no way for the rock to move, meaning no plate tectonics, no volcanoes, and no atmosphere.”

Veteran Gemological Institute of America researcher Jim Shigley tells JCK that the the results support the idea that carbon in the form of diamond may be a major component of the interior of some solid planets. ” As with the previous case of diamond being detected in stars, the amount of diamond could be very great,” he says.

“These diamond planets are a new member of the family than has been described so far,” says Panero. “As we proceed, I suspect we’ll find all sorts of strange compositions of planets, some with atmospheres, some with oceans made of liquid besides water, and more variety that could possibly harbor life.”